<?php
/**
 * Smarty plugin
 *
 * @package    Smarty
 * @subpackage PluginsShared
 */

/**
 * evaluate compiler parameter
 *
 * @param array   $params  parameter array as given to the compiler function
 * @param integer $index   array index of the parameter to convert
 * @param mixed   $default value to be returned if the parameter is not present
 *
 * @return mixed evaluated value of parameter or $default
 * @throws SmartyException if parameter is not a literal (but an expression, variable, …)
 * @author Rodney Rehm
 */
function smarty_literal_compiler_param($params, $index, $default = null) {
	// not set, go default
	if (!isset($params[$index]))
	{
		return $default;
	}
	// test if param is a literal
	if (!preg_match('/^([\'"]?)[a-zA-Z0-9]+(\\1)$/', $params[$index]))
	{
		throw new SmartyException('$param[' . $index . '] is not a literal and is thus not evaluatable at compile time');
	}

	$t = null;
	eval("\$t = " . $params[$index] . ";");

	return $t;
}
